The present invention relates to a semiconductor device and more particularly to a technique which can be effectively adapted to a semiconductor device provided with an input/output interface circuit suitable for a bus such as IIC bus.
An output circuit of a certain kind is required to conduct an operation to restrict signal variation speed such as rising rate or falling rate of an output signal for the suitable operation of a circuit system using the same output circuit, and therefore it is required for such output circuit to introduce a circuit structure suitable to such requirement. A circuit for the IIC bus which has been proposed by the Philips Corp. is provided with a restriction of this kind. The IIC bus is formed of a serial data line (SDA) and a serial clock line (SCL). Therefore, coupling among the less number of lines between the circuit systems becomes possible. IIC(I2C) is the trade mark of the Philips Corp. The U.S. Pat. Nos. 5,790,526 and 4,689,740 describe a circuit in relation to the IIC bus.